Tandem MS for Drug Analysis

Tandem MS for Drug Analysis
4/19/2017 Tandem MS for Drug Analysis Dr. Edward Randell

Tandem MS 4/19/2017 Mass Spectrometers Separate and measures ions based on their mass-to-charge (m/z) ratio. Operate under high vacuum (keeps ions from bumping into gas molecules) Key specifications are resolution, mass measurement accuracy, and sensitivity. Several kinds exist: for bioanalysis, quadrupole, time-of-flight (TOF) and ion traps are most used. Dr. Edward Randell

Tandem MS 4/19/2017 What is Tandem MS? Uses 2 (or more) mass analyzers in a single instrument One purifies the analyte ion from a mixture using a magnetic field. The other analyzes fragments of the analyte ion for identification and quantification. Mixture of ions Single ion Fragments Ion source MS-1 MS-2 Dr. Edward Randell

Tandem MS 4/19/2017 Analytical Assays used in Pharmaceutical Industry Labs for New Chemical Entities Method 1990 1998 2000 2006 HPLC (UV &Fluorescence) 75% 50-60% 20% 2% GC/MS 12% 3% LC/MS/MS 40-50% 60-75% 98% Immunoassay (ELISA/FPIA etc.) 10% table Dr. Edward Randell

Applications of Tandem MS
4/19/2017 Applications of Tandem MS Biotechnology & Pharmaceutical To determine chemical structure of drugs and drug metabolites. Detection/quantification of impurities, drugs and their metabolites in biological fluids and tissues. High through-put drug screening Analysis of liquid mixtures Fingerprinting Nutraceuticals/herbal drugs/tracing source of natural products or drugs Clinical testing & Toxicology inborn errors of metabolism, cancer, diabetes, various poisons, drugs of abuse, etc. Dr. Edward Randell

MS vs. MS/MS MS MS/MS GC HPLC CE Inlet Detect Mass Analyze Ionize
Tandem MS 4/19/2017 MS vs. MS/MS GC HPLC CE Inlet Detect Mass Analyze Ionize MS In the upper part of this slide, we can see a block diagram of a mass spectrometer. We have the sample inlet, the ion source, the mass analyser or separator, and the detection system. What we have in a tandem mass spectrometer is.... well, two mass spectrometers in tandem. We have the inlet system and the ion source and the first mass analyser, but what we have then is a region in which we can controllably break the ions down. That is, the ionic species passing out of the first mass spectrometer pass into this collision region and break down by colliding with a neutral target gas, typically argon. The fragmentation that occurs in the collision cell is highly dependent on the amount of energy we deposit into the molecules (by controlling the speed of the ions as they enter the collision cell, and the number of collisions they undergo with the target gas) and the chemical structure of the molecules. The fragments that are generated in the collision cell then pass through into the second mass analyser where they are separated according to their mass to charge ratios again, and we can record the MS/MS spectrum on the detector. The specificity of this experiment comes from the fact that all the fragment ions that are generated in the collision cell, and recorded in the spectrum, are derived from the mass that is passed through from the first mass analyser. We know, therefore, that all the product, or daughter ions, are all derived from a single precursor, or parent. If we are analysing a mixture of compounds, we are effectively separating them out according to their masses before we generate their mass spectra. This is not an easy concept to grasp straight off, so let's compare tandem mass spectrometry to GC-MS (which may or may not be in use in the audience's laboratory, but they are likely to have heard of it). Separation Identification Inlet Fragment Mass Analyze Ionize Mass Analyze Detect MS1 Collision Cell MS2 MS/MS Dr. Edward Randell

Mass Spectrometry +COH +CH3 CH3COCH3 CH3+COCH3 CH3C+OCH3 +COCH3 Sample
Tandem MS 4/19/2017 Mass Spectrometry CH3COCH3 Sample Inlet CH3+COCH3 Ionization & Adsorption of Excess Energy Mass Analysis CH3C+OCH3 +COCH3 +CH3 +COH Fragmentation (Dissociation) Detection A mass spectrometer is comprised of a number of discrete components. Firstly, the sample needs to be introduced into the mass spectrometer. In all the work in this presentation, a solution of the sample to be analysed is infused or injected into the mass spectrometer. In order to then analyse molecules by mass spectrometry, it is necessary to generate gas-phase ions to ionise the sample. There are a variety of methods of ionisation that can be used to generate the species of interest, but the one we will be focusing on today is electrospray ionisation.... but we'll cover that in more detail in a couple of slides, or so. Predominantly, though, the mechanism of ionisation is molecular protonation, or the addition of another cationic (e.g. sodium or ammonium ion) species to the molecule of interest. Depending on how much energy is applied during the ionisation process, we may or may not induce fragmentation in the molecule. Typically, electrospray is a soft ionisation technique which means that we see predominantly molecular related species in the mass spectrum. Once we have generated the ions, we separate them out according to, strictly, their mass to charge ratios. As most of the ions we will be considering today will appear as the singly charged species, what we are in effect measuring is the mass of the molecules and fragments generated in the ionisation process. The ions separated out are then detected at the end of the instrument, the information is passed to a computer, and we see the mass spectrum. The mass spectrum is typically represented with the mass (or m/z) of the ions on the abscissa and the relative signal strengths on the ordinate. Now, how does tandem mass spectrometry differ from single stage mass spectrometry that we have seen in this slide. Dr. Edward Randell

Multidimensional Analyses
Tandem MS 4/19/2017 Multidimensional Analyses m/z m/z response m/z chromatogram time Dr. Edward Randell

Different Types of MS Tandem MS Triple Quatrupole Hybrid Instruments
4/19/2017 Different Types of MS Tandem MS Triple Quatrupole Hybrid Instruments ESI-QTOF Electrospray ionization source + quadrupole mass filter + time-of-flight mass analyzer MALDI-QTOF Matrix-assisted laser desorption ionization + quadrupole + time-of-flight mass analyzer Dr. Edward Randell

Tandem MS 4/19/2017 LC-MS/MS Dr. Edward Randell

Analytical Quadrupole
Tandem MS 4/19/2017 Analytical Quadrupole Dr. Edward Randell

Quadrupole Theory Pre-filter Quadrupole Mass Filter
Tandem MS 4/19/2017 Quadrupole Theory Pre-filter Quadrupole Mass Filter Stable Trajectory Unstable Trajectories Only ions with the correct m/z values have stable trajectories within an RF/DC quadrupole field. Ions with unstable trajectories collide with the rods, or the walls of the vacuum chamber, and are neutralised. Dr. Edward Randell

Tandem Quadrupole Collision cell MS2 MS1 Tandem MS 4/19/2017
This is a picture taken of the insides of a Quattro micro where we can see the components of MS1 (left), the collision cell (centre) and MS2 (right). This is an area of the instrument that the user would never be expected to access, but it is worth seeing nonetheless. Dr. Edward Randell

Components of Tandem Mass Spectrometer
Tandem MS 4/19/2017 Components of Tandem Mass Spectrometer Ionization Source Mass Spectrometer Collision Cell Mass Spectrometer Detector ESI APPI APCI MALDI Quatrupole Magnetic Sector Time-of-flight Quatrupole Magnetic Sector Argon Xenon Collision cell MS1 MS2 Dr. Edward Randell

Sample introduction Ion Souce Transforms sample molecules to ions
Tandem MS 4/19/2017 Sample introduction Ion Souce Transforms sample molecules to ions Soft ionization Places positive or negative charge on the analyte without significantly fragmenting the analyte M+1 ion (or M-1 ion) No need to volatilize Down to fmol detection limits Atmospheric Pressure Ionization (API) Electrospray MALDI APCI APPI Dr. Edward Randell

The Macabre History of Electrospray
Tandem MS 4/19/2017 The Macabre History of Electrospray The Abbé Nollet experimented with electrified liquids in the 18th century ! He observed that when a person was connected to a high-voltage generator he/she would not bleed normally after cutting ...blood “sprayed” from the wound ! F. Lemière, LC•GC Europe “LC-MS Supplement”, December 2001, p29-35 The earliest we have been able to find is this report from an 18th century scholar, who observed that when a person was connected to a high-voltage supply, he would not bleed normally on cutting, but blood would be sprayed from the wound. If I was a good scientist, I would have repeated this work and verified the observation. However, I have yet to find a volunteer...... I do not recommend you try this at home! Dr. Edward Randell

The Electrospray Phenomenon
Tandem MS 4/19/2017 The Electrospray Phenomenon The first report of the electrospray phenomenon was by Zelene in In this photograph you can see a solution inside a fine capillary, to which a high voltage has been applied. The plume of the right hand side of the picture is the spray that is ejected from the nozzle as a fine mist. However, if you look hard enough, you might be able to find earlier reports.... J. Zelene, Phys. Rev., 10, 1-6 (1917) Dr. Edward Randell

Ionization Source Tandem MS 4/19/2017
However, back to more serious things…… This is a schematic representation of the ZSPRAY™ ionization source that we use in our instruments. The sample, in the flowing solvent stream, is introduced into the source through a 125µm stainless steel capillary and passed into the ionization/source region. The sample is introduced at a flow rate in the range of 10 – 100µL per minute and we have to generate a fine spray in order to generate the ions from the sample being analyzed. The fine spray is generated by the action of two phenomena: nebulization and electrospray. The sample passing through the probe is nebulized using a stream of nitrogen gas—similar to what you would see in a perfume atomizer. The stainless steel capillary is held at a high voltage potential—typically 2 – 4kV—while the rest of the instrument is held at about ground potential. This means that we have a very strong electric field between the end of the probe and the entrance into the mass spectrometer and this causes considerable polarization in the droplets formed in the nebulization, leading to the formation of ions—this is the electrospray phenomenon that we saw a couple of slides ago. The ions are generated at atmospheric pressure and then pass through two orthogonal orifices in order to get into the vacuum system of the mass spectrometer. This is what gives ZSPRAY its name. Because we have a right angled turn, all the non-volatile material in the sample passes straight on into a baffle plate, and does not clog up the orifice into the instrument—but we are not interested in that material—only the ions that have been formed. The ions are guided through these small holes (they are only 400µm in diameter) by a combination of gas dynamics (first hole) and electrostatic lensing (second hole). Dr. Edward Randell

Ionization Source Sample Cone Spraying Needle Vacuum Isolation Valve
Tandem MS 4/19/2017 Ionization Source Spraying Needle Sample Cone Orifice = 400µm …and a close up photo showing some of the detail of the source. Vacuum Isolation Valve Dr. Edward Randell

Ion Sources make ions from sample molecules
Tandem MS 4/19/2017 Ion Sources make ions from sample molecules Electrospray ionization: High voltage applied to metal sheath (~4 kV) Sample Inlet Nozzle (Lower Voltage) Charged droplets + MH+ MH3+ MH2+ Pressure = 1 atm Inner tube diam. = 100 um Sample in solution N2 N2 gas Partial vacuum Dr. Edward Randell

ESI Spectrum of Trypsinogen (MW 23983)
Tandem MS 4/19/2017 ESI Spectrum of Trypsinogen (MW 23983) M + 15 H+ 1599.8 M + 16 H+ M + 14 H+ 1499.9 1714.1 M + 13 H+ 1845.9 1411.9 1999.6 2181.6 m/z Mass-to-charge ratio Dr. Edward Randell

Tandem MS 4/19/2017 APCI Dr. Edward Randell

Tandem MS 4/19/2017 APPI Dr. Edward Randell

MALDI: Matrix Assisted Laser Desorption Ionization
Tandem MS 4/19/2017 Sample plate Laser hn 1. Sample is mixed with matrix (X) and dried on plate. 2. Laser flash ionizes matrix molecules. 3. Sample molecules (M) are ionized by proton transfer: XH+ + M  MH+ + X. MALDI: Matrix Assisted Laser Desorption Ionization MH+ Grid (0 V) +/- 20 kV Dr. Edward Randell

The mass spectrum shows the results
Tandem MS 4/19/2017 The mass spectrum shows the results MALDI TOF spectrum of IgG MH+ 10000 20000 30000 40000 Relative Abundance (M+2H)2+ (M+3H)3+ 50000 100000 150000 200000 Mass (m/z) Dr. Edward Randell

Components of Tandem Mass Spectrometer
Tandem MS 4/19/2017 Components of Tandem Mass Spectrometer Ionization Source Mass Spectrometer Collision Cell Mass Spectrometer Detector ESI APPI APCI MALDI Quatrupole Magnetic Sector Time-of-flight Quatrupole Magnetic Sector Argon Xenon Collision cell MS1 MS2 Dr. Edward Randell

Operation Modes Product Ion Scanning Precursor Ion Scanning
Tandem MS 4/19/2017 Operation Modes Product Ion Scanning Analyzes all products of a single precursor Precursor Ion Scanning Analyzes all precursors of a single charged product Neutral Loss Scanning Analyzes all precursors of a single uncharged product Multiple Reaction Monitoring Analyzes for specific precursors producing specific products. Dr. Edward Randell

Full Scan Acquisition Mode
Tandem MS Collision cell MS1 MS2 4/19/2017 MS1 MS2 Collision Cell Scanning Rf only, pass all masses Full Scan Acquisition Mode So, what kind of experiments can we conduct, and importantly, what type of data can we generate from a tandem quadrupole mass spectrometer? First, in a full scan acquisition the quadrupole mass filter is scanned over a user-defined mass range. Thus, all ions generated in the source region of the instrument will be sorted, or filtered, by the first quadrupole mass spectrometer. Only those compounds having masses within the user-defined range will be allowed to pass to the detector. These are the only compounds we will monitor in this experiment. SCANNING MODE: The first quadrupole mass analyzer is Scanning over a mass range. The collision cell and the second quadrupole mass analyzer allow all ions to pass to the detector. Dr. Edward Randell

Mass Spectrum: Progesterone
Tandem MS 4/19/2017 Mass Spectrum: Progesterone [M+H]+ Full Scan Acquisition Mode Here is a mass spectrum spanning the range m/z 200 – 400, showing principally one peak at m/z This peak corresponds to the protonated progesterone molecule. Remember in a mass spectrometer we must first generate ions in order to analyze them. In this case the instrument is operating in the positive ion mode. Thus, only positive ions are monitored. Here we see the positive ion for progesterone (or [M+H]+) at m/z This is a very clean mass spectrum because the sample was simply dissolved in solvent and introduced into the mass spectrometer. In order to analyze complex mixtures of compounds, with their associated matrices, we need to do different experiments, like… Dr. Edward Randell

Product ion scanning Collision cell MS1 MS2 Argon gas
Tandem MS Collision cell MS1 MS2 4/19/2017 Argon gas Product ion scanning …product ion scans. Product ion scans provide useful structural information about compounds as well as aiding in the selection of product ions for quantitation when using Multiple Reaction Monitoring (MRM). Products Precursor Static (m/z 315.1) Scanning The first quadrupole mass analyzer is fixed at the mass-to-charge ratio (m/z) of the precursor ion to be interrogated while the second quadrupole is Scanning over a user-defined mass range. Dr. Edward Randell

Collision induced dissociation
Tandem MS 4/19/2017 Collision induced dissociation Argon gas Precursor ion Product ions This slide demonstrates the principles of collision-induced dissociation. Ions from MS1 – the precursor ions pass from MS1 into the collision region. Inside the collision cell, argon gas is maintained at a known pressure. The ions from MS1 collide with the gas and some of the translational (kinetic) energy of the ions is converted into internal energy. Molecules are fragile, and if sufficient energy is put into the molecules, they will break at their weakest points. This fragmentation may not be predictable (it is not quantised as in NMR or infra-red spectrometry/spectroscopy), but it is very reproducible. The ions pass through the collision cell and out of the other side, into MS2, where the fragments are measured. The fragmentation of the selected precursor ions can be controlled by varying: (1) the speed of the ions as they enter the collision region (the collision energy) or (2) the number of collisions undertaken (the collision gas pressure) In the collision cell, the TRANSLATIONAL ENERGY of the ions is converted to INTERNAL ENERGY. Collision conditions (FRAGMENTATION) is controlled by altering: The collision energy (speed of the ions as they enter the cell) Number of collisions undertaken (collision gas pressure) Dr. Edward Randell

Product Ion Spectrum: Progesterone
Tandem MS 4/19/2017 Product Ion Spectrum: Progesterone Mass Spectrum from MS1 Precursor ion Product ion scanning Product ions Product ion spectrum from MS2 Dr. Edward Randell

Product ion scanning  collision energy >  fragmentation 5eV 10 eV
Tandem MS 4/19/2017  collision energy >  fragmentation 5eV 10 eV Product ion scanning 20 eV 30 eV 40 eV Dr. Edward Randell

Precursor ion scanning
Tandem MS Collision cell MS1 MS2 4/19/2017 Precursor Ion Scan Argon gas Precursor ion scanning In a precursor ion scan, the second quadrupole mass spectrometer is held static (or fixed) at the mass-to-charge ratio of the known product ion, e.g. m/z 85 in the case of the acylcarnitines. Meanwhile, the first quadrupole mass spectrometer is scanned over a user-defined mass range to scan for all compounds within that mass range that give rise to this common product ion. Thus, it is possible to analyze a complex mixture of compounds and identify only those with a common structure. Product Precursors Scanning Static The first quadrupole mass analyzer is Scanning a mass range while the second quadrupole is fixed, or Static, at the mass-to-charge ratio (m/z) of a product ion known to be common to the analytes in a mixture. Dr. Edward Randell

Precursor ion scanning
Tandem MS 4/19/2017 Acylcarnitines Derivatization and Fragmentation R=0 to 18 carbon alkyl chain. - RCOOH -(CH3)3N -C4H8 CID Butylation CH2 CH RCOO H COOH (CH3)3N COOC4H8 [ ]+ (m/z 85) Precursor ion scanning This is the generic structure for the acylcarnitines. The species differ in the variation of this R group on the top of the molecule. It is the free carboxylic acid group at this end of the molecule that is esterified during the butylation step. We then protonate the butyl ester of the acylcarnitine and pass it into the collision cell of the mass spectrometer. Now, all derivatized acylcarnitines, regardless of the nature of the R group, will fragment in the collision cell and lose trimethylamine, a free carboxylic acid from this region of the molecule, and a butene molecule from the ester. This leaves us with a common fragment, regardless of the nature of the acyl group, of mass to charge 85. So, how do we operate our mass spectrometer to analyse for acylcarnitines… All compounds of this type fragment to produce the 85 ion. Dr. Edward Randell

Normal Acylcarnitine Profile
Tandem MS 4/19/2017 Normal Acylcarnitine Profile d3-C16 carnitine d3-free carnitine 225 250 275 300 325 350 375 400 425 450 475 500 m/z 100 % Precursor ion scanning Here is an acylcarnitine profile generated from the blood spot of a healthy patient. What we see are peaks attributable to free carnitine at m/z 218, acetyl carnitine at m/z 260, and palmitoyl carnitine at m/z 456. In this particular sample preparation for the data I am showing today, we used three isotopically labelled internal standards for quantification: trideuterated C2 carnitine (263), trideuterated C8 carnitine (347) and trideuterated C16 carnitine (459). I believe that now a number of other isotopically labelled carnitines are commercially available, but they are expensive, and it may not be financially viable to use too many - it really depends on what information you wish to garner. I have a number of data sets here with disease states apparent. C2 carnitine d3-C3 carnitine C16 carnitine d3-C8 carnitine Dr. Edward Randell

Neutral loss scanning Collision cell MS1 MS2 Argon gas Scanning (M)
Tandem MS Collision cell MS1 MS2 4/19/2017 Argon gas Neutral loss scanning Products Precursors Scanning (M) Scanning (M-102) In a neutral loss scan the two quadrupole mass filters are Scanning synchronously at a user-defined offset. The neutral loss is known to be common to the analytes in a mixture. Dr. Edward Randell

Butyl formate Neutral loss of 102Da
Tandem MS 4/19/2017 Neutral and Acidic Amino Acids Derivatization and Fragmentation (Generic) Neutral or Acidic AA HCl Amino acid butyl ester Butanol Neutral or Acidic AA Fragmentation Fragment Butyl formate Neutral loss of 102Da Dr. Edward Randell

Normal Amino Acid Profile
Tandem MS 4/19/2017 Normal Amino Acid Profile d3-Leu d4-Ala d3-Met d5-Phe d6-Tyr d8-Val Gly Ser Pro Glu Deuterated internal standards for quantification Neutral loss scanning Dr. Edward Randell

Multiple Reaction Monitoring
Tandem MS Collision cell MS1 MS2 4/19/2017 Argon gas Multiple Reaction Monitoring Product(s) Precursor(s) Static (m/z 315.1) Static (m/z 109.0) Both the first and second quadrupole mass analyzers are held Static at the mass-to-charge ratios (m/z) of the precursor ion and the most intense product ion, respectively. Dr. Edward Randell

Specificity of Detection for LC
Tandem MS 4/19/2017 Specificity of Detection for LC UV – chromophore all compounds with a chromophore responding at the selected wavelength will interfere MS – molecular mass interference from isobaric compounds chemical noise MS/MS – molecular mass and structural information interference from structural isomers only Dr. Edward Randell

HPLC-UV Analysis of Sirolimus in Whole Blood
Tandem MS 4/19/2017 HPLC-UV Analysis of Sirolimus in Whole Blood 1. Wash all glassware in methanol x2 and tert-butyl methyl ether (TBME) x2. 2. Place 50L of internal standard (in methanol) into each screw-cap glass tube. 3. Add 200L Sirolimus calibrator (5x concentrated in methanol) or 200L methanol for patient samples. 4. Add 1.0mL blank whole blood to calibrators or 1.0mL patient whole blood. 5. Add 2.0mL 0.1M ammonium carbonate buffer. 6. Mix thoroughly. 7. Add 7.0mL TBME and extract for 15min. 8. Transfer upper layer to clean tube and re-extract lower layer with 7.0mL TBME. 9. Combine TBME extracts and evaporate to dryness. 10. Redissolve residue in 5.0mL ethanol and evaporate to dryness. 11. Redissolve residue in 1.0mL ethanol, transfer to Eppendorf tube and evaporate to dryness. 12. Redissolve residue in 100L 85% methanol Inject 80L (equivalent to 800L whole blood) and analyse using two 4.6mm x 250mm C18 columns connected in series (30min run time). . . . to show that large volumes of blood are used with multiple liquid liquid extractions; multiple transfer steps and multiple evaporation steps ending with a 30min chromatography run through two 25cm columns in series. Dr. Edward Randell

Sirolimus: HPLC - UV Example
Tandem MS Sirolimus: HPLC - UV Example 4/19/2017 . . . in fact it's this tiny peak here and this represents a concentration of over 11ng/mL which almost at the upper limit of the recommended range for this drug. Dr. Edward Randell

Immunosuppressant Sample Preparation LC-MS/MS Analysis
Tandem MS 4/19/2017 Immunosuppressant Sample Preparation LC-MS/MS Analysis Whole Blood (10mL - 40µL) Add ZnSO4 Soln. But before we analyze a whole blood sample we need to do a simple extraction, or clean up, step to extract the drugs from the whole blood, making the preparation suitable for LC-MS/MS analysis. This extraction protocol is shown above and includes: Add whole blood to either 96-well plate or Eppendorf tube. Add zinc sulphate to disrupt the cells and denature the proteins. Add acetonitrile to extract the drugs of interest and precipitate proteins. Centrifuge and inject the supernatant, avoiding the protein pellet. This is a generic method that works well with the three main immunosuppressants in routine use. Add 2 volumes MeCN with IS, Seal & Vortex Mix Centrifuge, Inject mL Dr. Edward Randell

Sirolimus: MS Spectrum
Tandem MS 4/19/2017 Sirolimus: MS Spectrum [M+NH4]+ Full Scan Acquisition Mode [M+Na]+ [M+Li]+ [M+H]+ [M+K]+ Dr. Edward Randell

Sirolimus: LC-MS (SIM) vs LC-UV
Tandem MS 4/19/2017 30µg / L SIR m/z 821 HPLC-MS Single ion monitoring (MS) This slide illustrates the selectivity of detection achieved using a triple quad vs a single quad. Analysis of the same samples by single quad (SIR) and triple quad (MRM) reveal the presence of interferences in the SIR channel. The In the SIR channel, the Tacrolimus signal can only be seen at the highest concentration and accurate integration is impossible. Extensive sample preparation and chromatography would be necessary to remove these interferences. 1.5 min HPLC-UV Dr. Edward Randell

Sirolimus: MS Spectrum
Tandem MS 4/19/2017 Sirolimus: MS Spectrum [M+NH4]+ Full Scan Acquisition Mode [M+Na]+ [M+Li]+ [M+H]+ [M+K]+ Dr. Edward Randell

Product ion scanning Ar (2.5 – 3.0e-3mBar) Collision Cell MS1 MS2
Tandem MS 4/19/2017 Ar (2.5 – 3.0e-3mBar) Collision Cell MS1 MS2 Products Product ion scanning Precursor Static (m/z 821.5) Scanning The first quadrupole mass analyzer is fixed, or Static, at the mass-to-charge ratio (m/z) of the precursor ion to be interrogated while the second quadrupole is Scanning over a user-defined mass range. Dr. Edward Randell

Product ion scanning Mass spectrum from MS1
Tandem MS 4/19/2017 NH4+ Mass spectrum from MS1 Product ion spectrum from MS2 Product ion scanning Dr. Edward Randell

Multiple Reaction Monitoring
Tandem MS 4/19/2017 Ar (2.5 – 3.0e-3mBar) Collision Cell MS1 MS2 Product(s) Multiple Reaction Monitoring Precursor(s) Static (m/z 821.5) Static (m/z 768.5) MS/MS : Compound-Specific Monitoring Dr. Edward Randell

Sirolimus LC-MS(SIM) vs LC-MS/MS (MRM)
Tandem MS Sirolimus LC-MS(SIM) vs LC-MS/MS (MRM) 4/19/2017 MRM m/z 821>768 3µg / L 30µg / L SIR m/z 821 Multiple Reaction Monitoring This slide illustrates the selectivity of detection achieved using a triple quad vs a single quad. Analysis of the same samples by single quad (SIR) and triple quad (MRM) reveal the presence of interferences in the SIR channel. The In the SIR channel, the Tacrolimus signal can only be seen at the highest concentration and accurate integration is impossible. Extensive sample preparation and chromatography would be necessary to remove these interferences. Dr. Edward Randell

Tandem MS for Drug Analysis

Similar presentations

Presentation on theme: "Tandem MS for Drug Analysis"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Tandem MS for Drug Analysis

Similar presentations

Presentation on theme: "Tandem MS for Drug Analysis"— Presentation transcript:

Similar presentations

About project

Feedback